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Caption

Right-hand rule for wires, illustration. This rule is used to determine the direction of the magnetic field present around a wire carrying an electric current. The wire is gripped with the thumb pointing in the direction of the current flow (arrowed) from positive (+) to negative (-). The direction of the fingers enclosing the wire follow the direction of the magnetic field. The field lines are shown here in the form of small magnet dipoles. The convention is that the field lines run from south (white) to north (red), and are seen forming clockwise circles when looking down the wire in the direction of the current flow. If the polarity of the current is reversed, the magnetic field direction also switches.